In the case of a known pressing plunger mechanism as disclosed in DE 30 40 762 C2 of the applicant the pressing plunger holders are driven by a crank gear (column 6, lines 22 and 23). This construction is expensive and takes up a large amount of space in the glassware forming machine.
An alternative type of drive for the pressing plunger holders is known from U.S. Pat. No. 5,411,564. These pressing plungers are accordingly each moved axially in a reciprocating manner by a piston-cylinder unit between a pressing and an inoperative position. This pressure medium drive is supported by a first housing which is disposed so that it can be adjusted with respect to a machine frame in parallel with the longitudinal direction of the pressing plungers by means of a further drive formed as a spindle drive. This latter-named spindle drive is formed by a plurality of threaded spindles extending in parallel with each other, which are engaged with spindle nuts disposed in a non-rotatable manner in a base of the housing, which are united on the input side by a gear mechanism and which are connected to a drive. However, precise movement control with a pressure medium drive is barely possible or is only possible at great expense.